npapi plugin for chrome proxy settings

As you may already know, chrome does not have a proxy management interface and it uses the system's proxy settings for that. If you want to change those settings from an extension you need to develop a plugin which communicates with NPAPI in order to apply settings.

The plugin exposes it's methods/functions to javascript which can be used inside the extension to retrieve the current proxy/set the proxy.

I need such a plugin which will work on all major platforms (linux, windows, mac) and both on x86, x64 based systems. I only need two functions exposed so it should be fairly simple for a C++ programmer to get into the basics and build them.

First function:

getCurrentProxy - will return the current proxy set into the browser/system respectively:

1. ip address

2. port

3. protocol (http, socks4, socks5)

setProxy (ip_address, port, protocol) - will set the system proxy based on the parameters received. Will also validate the ip_address to be a valid ip, port to be a numerical value between 2 and 5 digits and protocol must be in the list: (http, socks4, socks5)